Central-energy telephone system



PATENTED PEB. 9, 1904.

J. E. LENDI. CENTRAL ENERGY TELEPHONE SYSTEM.

APPLICATION FILED DBO. 19, 1900.

N0 IODIZL.

bmah-Hup UNITED STATES Patented February 9, 1904.

PATENT OFFICE.

JOHN HENRY LENDI, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGG SVVITCHBOARD AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS.

CENTRAL-ENERGY TELEPHONE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 751,797, dated February 9, 1904. Application led December 19, 1900. Serial No, 40,403. (No model.)

T0 @ZZ whom t may concern:

Be it known that I, JOHN HENRY LENDI, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Central-Energy Telephone Systems, of which the following is afull, clear, concise, and exact description, reference being hadV to the accompanying drawings, forming apart of this specification.

My invention relates to a central-energy telephone system, my object being more particularly to provide an improved form of signaling apparatus at the central station.

My object, moreover, is to provide an -improved form of combined relay and repeatingcoil.

I have hereinafter illustrated and described one specific embodiment of my invention for the purpose of illustrating the general principle underlying the same, and in accordance therewith I employ a pair of repeating-coils, the windings of the two coils being in parallel with each other. One pair of windings of each repeating-coil is adapted to be connected in circuit with one of two connected subscribers, while the remaining windings of the two repeating-coils are adapted to be connected with the other of the two connected subscribers. In order to make the repeatingcoils perform the function of relays for operating the supervisory signals, I associate with the windings means whereby the magnetism of the core of one of the repeating-coils is under the control of one of the two connected subscribers, while the magnetism of the core of the other repeating-coil is under the control of the other of the connectedsubscribers. To accomplish this result, a condenser may be interposed in the circuit of one of the windings of each repeating-coil, whereby the core will be magnetized by the remainingwinding alone. By placing one of these magnetized windings under the control of each of the connected subscribers the repeating-coils are individualized and may serve as relays for actuating the supervisory signals.

lVhile I have illustrated my invention in connection with one specific embodiment of the invention, it will be understood that the features of my invention are capable of other embodiments within the spirit of my invention, as more particularly set forth in the claims appended hereto.

I have illustrated my invention in the accompanying drawings, in which- Figure l is a diagram showing the two telephone-lines and the cord-circuit for connecting the same for conversation. Fig. 2 is a diagram showing the talking-circuit. Fig. 3 is a diagram showing the manner of mounting the windings of the relays and repeatingcoils upon a common core. Fig. 4 is a detail view of the plug-seat switch.

Like characters refer to like parts in the several figures.

The telephone-line A extends in two limbs a c to the central station, wheresaid limbs terminate, respectively, in the springs c2 a3, the spring a2 normally resting against back Contact 1, which is connected to ground, the

spring c3 normally resting against back contact 2, which is connected through individual annunciator cto conductor 3. The springs o2 and (t3 carry armatures resting opposite the poles of a relay-magnet and the spring a2 when attracted is adapted to engage front contact 4, which is connected with the linesprings CZ' d of the spring-jacks or switchsoclrets (Z CZ. The spring a3 is adapted when attracted to engage contact 5, which is connected with the sleeves (Z2 (Z2 of .the springjacks. Moving with the spring a2, but insulated therefrom, is a spring @4, connected to ground through a resistance c and adapted when the relay is energized to engage contact 6, which is connected with the test-rings cld. One end of the winding of relay is connected with conductor 3 and the other end is connected with the contact-springs (Z3 d3, Which springs are mounted to move with, but insulated from, the line-springs d cZ, respectively. IVhen the plug is inserted in the spring-jack, the line-spring d is moved by the tip thereof to carry the spring cl3 into engagement with thegrounded contact di.

' -strands s' and t' are included the windings h3.

The subscriber is provided at the substation with the usual microphone f, receiver f,`and switch-hook f2, adapted when the line is not in use to engage contact 7, which is connected through bell f3 and condenser Z3 to ground. When the telephone is removed from the hook, the hook engages contact 8, which is connected with the telephone transmitter and receiver. rlhe telephone-line B (shown at the right oi' the drawings) is like the telephoneline A and is provided with the same parts and mechanism, and like parts have been indicated by the same reference-letters employed in connection with the line A.

The connecting mechanism at the central station comprises an answering-plug p and a calling-plug 0, the tip p' of the plug p being connected with the tip-strand Z, while the sleeve p2 of the plug is connected with the sleeve-strand s. The tip 0' of the plug 0 is connected with the tip-strand Z, while the sleeve 02 is connected with the sleeve-strand s. The plugs are joined together through two repeating-coils, the windings of which are in parallel with each other. Connected between the strands s and Z are of the repeating-coil /L and the windings le and 7a2 of the repeating-coil 7c. Between the and It* of the repeating-coil ZL and the windings v and k* of the repeating-coil Zr. The battery 9 is connected between the windings L and ZL? by means oi' conductors 9 and 10, while the battery 7" is connected between the coils 7c3 and Z2* by means of conductors 11 and 1Q. n A condenser Z is interposed between the windings h3 and if, and a condenser Z is interposed between the windings la' and k2.

' One pole of battery r is connected with the conductor 3, with which line A is in connection, and ne pole of the battery r is in communication with conductor 3, connected to line B. rEhe opposite poles of the batteries 7' and 0" are grounded.

and this spring normally engages contactA rlhe repeating-coils Zt and Z9 in addition to their function as repeating-coils serve also as relays for actuating the supervisory signals. The relay ZL controls the supervisory signal, which is adapted to be actuated by the calling subscriber, while the relay is adapted to control the supervisory'signal actuated by the called subscriber. A spring m carries an armature situated opposite the pole of relay 13, which isconnected through the supervisory lamp or signal m with one pole of the battery 0. The spring m is connected through the spring m2 and contact 14 of a plug-seat switch to the opposite pole of the battery r.

Vhenthe answering-plug is in the seat, the spring m2 is moved out of engagement with Contact 14 to open the circuit through the lamp m', and when the plug is removed from the seat the spring m2 and contact 14 rest in contact. Likewisea spring e carries anarthe windings 7L and if mature resting opposite the pole of relay 7c and normally engaging a contact 15, connected through lamp c with one pole of battery 1". The spring c is connected with the opposite pole of the battery r' through spring v2 and contact 16 oi' a plug-seat switch adapted to be actuated by the calling-plug 0. As shown in Fig. 3, the windings ZL h2 and LS of the relay are wound upon a single core h5.

In the tip-strand t a ringing-key g' is provided, normally resting against contact 17 and adapted when depressed to engage contact 18 to connect the grounded generator g in circuit with the tip 0 of the calling-plug. The operators telephone set is adapted to be bridged between the strands s' t. A condenser Z2 is included in circuit therewith.

I will now describe the operation of making and disconnecting the connection between two subscribers: Supposing subscriber A desirous of conversing with subscriber- B, he removes histelephone-receiver Jfrom the hook, thereby closing the circuit of battery fr through the individual annunciator 0 belonging to line A. rlhis circuit may be traced from battery o" over conductor 3, annunciator c, contact 2, spring (Z3, limb e', contact 8, hook f2, limb a, spring a2, contact Z toground, and thence to the grounded pole oi' battery fr. Annunciator c is thus actuated to attract the attention of the operator, who thereupon removes the answering-plug p from its seat'in the plug-seat switch and inserts the same in the spring-jack belonging to the subscriber A. The insertion of the plug p moves the' spring Z3 into contact with contact di, thus closing circuit of battery r from ground over conductor 3, through relay Z), spring (Z3, Contact Zi to ground. The relay Z) is thus energized, attracting the armatures carried on springs Z2 and a3 and moving said springs into engagement, respectively, with contacts 4: and 5. rIhe annunciator c is thus disconnected from circuit, and the spring Z2 is connected with the line-spring Z' of the spring-jack, while the spring a3 is connected with the terminal sleeve Z2 of the springjack. The spring-jack terminals are thus connected with the limbs of the telephone-line.

energized thus closino s ring into contactb 5 C C) with contact 6, and a testing-circuit will thus be closed Jfrom battery r' through coil ,764, tipstrand t', tip 0', test-ring d5, contacts 6 and a* to ground and thence back to the battery. Since the telephone-receiver-of the operators IOO IIO

ISO

set is in circuit with the windingJi, the breaking of the circuit as the tip is removed from contact with the test-ring d will cause a kick of self-induction to pass back through the operator-s receiver, thereby causing a click which may serve as a test-signal. If the line is not in use and the relay b denergized, the circuit will be opened between the contacts 6 and at" and no click will be heard in the operators telephone. The operator hearing no click in her telephone when the line B is tested, and thus learning that the line is not busy, will insert the calling-plug 0 in the springjack belonging to line B and will thereupon depress ringing-key g, and the current from generator g will pass from ground over strand t an d limb c of subscriber B to ground through his bell f3, thereby ringing the same. hen subscriber B responds and lifts his receiver from the hook, the limbs a and 6.1/ will be closed together in metallic circuit, and the circuit through the battery fr will thus be closed through the coils if of the relay f and through the strands s t and the limbs a a of the telephone-line. rEhe relay will thus be energized, and the armature carried upon spring' V will be attracted to separate contacts c' and l5, and thereby open the circuit through the lamp 0;', thus extinguishing the same. Upon the extinguishment of the lamp the operator will know that the subscribers are in conversation. During the conversation the lamps m' and o remain extinguished. The talking-circuit is illustrated in diagram in Fig. 2. W'hen subscriber A is talking and his microphone f is actuated to vary the resistance, the potential between the points and a" is correspondingly varied. The coils /t if and le? are thus subjected to varying currents, which induce corresponding currents in the secondaries LS it* and if if, respectively, of the relays or repeating-coils L?. Likewise when subscriber B is talking the difference of potential between the points y g/ is varied, and the coils f3 L* and /Ls act as the primaries, while the coils 7a2 and t" ft2 act as the secondaries, of the repeating-coils. For talking purposes the two repeating-coils are thus in parallel with each other. Since, however, the repeating-coils are also to serve as relays, it is necessary to provide means whereby the relay it may be controlled by a switch at the substation A, while the relay 1 may be controlled by a switch at the substation B. For this purpose the condensers Z l are employed, whereby the current from battery fr is prevented from arfccting the core of relay z., while the current from battery /r is prevented from affecting the core of relay 7c. In this manner each relay may be controlled from but one of the substationsthat is, relay z, from substation A, while' the relay may be controlled only from substation B. At the completion of the conversation one or both of the subscribers hang up their receivers, thus -clearing-out signal'.

lighting the lamps belonging to their respective lines. Thus when subscriber A hangs up his receiver the limbs a and a' are disconnected and the circuit of battery r through the windings fr 7a2 is thus opened. The spring m thus falls back into contact with contact 13 to close the circuit through lamp m. Likewise the hanging up or' the receiver by subscriber B opens the limbs t a at the switch-hook, thereby opening the circuit of Abattery fr through the coils Zi 'fi of relay lr, which deenergizes said relay and closes the circuit through lamp o. Seeing the lamps lighted, the operator knows that the subscribers are through conversing and withdraws the plugs p and o and returns the same to their respective seats. The return of the plugs to their respective seats separates the contacts of the plug-seat switches, thereby opening the local circuits through the lamps m o and extinguishing the same. The-relay and the plugseat switch thus cooperate in controlling the The lamp of the calling subscriber is lighted upon the removal of the plug from its seat and is extinguished upon the insertion of the lplug and the consequent energization of the relay. lThe lamp of the called subscriber is lighted upon the removal of the calling-plug from its seat and is extinguished when the called subscriber removes his receiver from the hook. The lamp is lighted when the subscriber hangs up his telephone at the completion of the conversation and is extinguished upon the return of the plug to its seat.

I disclaim herein the matter claimed in the patent to Francis L Dunbar for telephoneswitchboard systems, dated November 12, 1901, No. 686,272.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. The combination with a pair of telephonelines adapted to be connected together for conversation through the windings of a repeatingcoil, of a source of electricity adapted to be connected in circuit with one of said windings, a switch at the substation for controlling the circuit of said source through said winding, a signaling' device controlled by said winding, means for rendering the other winding opaque to the passage of an operative continuous current, and a signal-controlling electromagnet and separate source or' current in circuit with the telephone-line connected with said latter'- mentionedwinding,substantially as described.

2. The combination with apair of telephonelines adapted to be united for conversation through a pair of repeating-coils having the corresponding windings thereof connected in parallel, of means for sending continuous current through one winding or' each repeatingcoil, means for rendering the other winding or' each repeating-coil opaque to the passage of continuous currents, one or' the windings adapted to be traversed by continuous currents being in circuit with each telephone-line and switches at the substations for controlling the circuits through the respective windings connected therewith, substantially as described.

3. The combination with a connecting-plug and aplug-seat switch, of a combined relay and repeating-coil, one winding of said repeating-coil being opaque to the passage of continuous currents, the other winding constituting the relay-winding, and a signaling device controlled by said relay and plug-seat switch, substantially as described.

4. The combination with a connecting-plug and the strands of acord-connector, of a plugseat switch, a combined relay and repeatingcoil having one winding connected between said strands, a charging source of electricity in circuit with said windings, means for rendering the other winding of the repeating-coil opaque to the passage of continuous currents, and a signaling device controlled by the action of said relay and plug-seat switch, substantially as described.

5. The combination with a telephone-line, of a connecting-plug and strands connected therewith, a combined relay and repeatingcoil having one winding connected between said strands, a charging source of electricity in circuit with said winding, means for rendering the other winding opaque to the passage of continuous currents, a switch at the substation for controlling the circuit of said source through the winding connected therewith, a plug-seat switch and a signaling device con trolled by said relay and plug-seat switch, substantially as described.

6. In a telephone system, two repeatingcoils having their corresponding windings connected in multiple, one winding of each being opaque to continuous currents and the other winding of each including a source of current,- substantially as described.

7. In a telephone system, the combination with a pair of telephone-lines, a pair of repeating-coils to unite said lines for conversation, one winding of each coil connected in the circuit oi' each line, means to prevent the passage of an operative continuous current through .one winding of each coil while permitting the passage of voice-currents, the other winding of each coil permitting the passage of both voice and continuous currents, a source of current included in the circuit of each line and the said latter winding, a switch at the substation controlling the circuit of the source through said winding, and apparatus at the central ottice controlled by the magnetism-of said coils, substantially as described.

8. In a telephone system, the combination with a pair of telephone-lines, a pair of repeati ing-coils to unite said lines for conversation, one winding of each coil connected in the circuit of each line, a condenser 1n the circuit of one winding of each coil to prevent the flow of continuous current therethrough while permitting the passage of voice-currents, the other winding of each coil permitting the passage of both voice and continuous currents, a source of current included in the circuit of each line and the said latter winding at the central oiiice, a switch at the substation controlling the circuit of the source through said winding, and signaling apparatus at the central oliice controlled by the said coils, substantially as described.

9. In a telephone system, the combination with a pair or' telephone-lines, a pair of repeating-coils to unite said lines for conversation, one winding of each coil connected in the circuit of each line, means to prevent the passage of an operative continuous current.

through one winding of each coil while permitting the passage of voice currents, the other winding of each coil permitting the passage of both voice and continuous currents, a source of current included in the circuit of each line and the said latter winding, a switch at the substation controlling the circuit of the said source through said winding, and signaling apparatus at the central oiice controlled by each said coil, substantially as described.

l0. In a telephone system, the combination with a pair of telephone-lines, of a pair of repeating-coils to unite said lines for conversation, one winding of each coil connected in the circuit of each line and in parallel therein, one winding of each coil being opaque to the passage of continuous current but open to the passage of voice-currents, the other winding of each coil being open to both voice and continuous currents, a source of current at the central oiice included in the circuit of each line, a switch at the substation of each line controlling the circuit of the said source through the said winding, and signaling apparatus at the central oiiice controlled by the magnetism of each said coil, substantially as described.

ll. In a telephone system, the combination with a pair of telephone-lines, a pair of repeating-coils to unite said lines for conversation, one winding of each coil connected in the circuit of each line and in parallel therein, a condenser in the circuit vof one winding of each said coil, the other winding of each coil being open to the passage of both voice and continuous currents, a source of current at the central oliice included in the circuit of each line and the said latter winding, a switch at the substation in each line controlling the circuit of the said source through said winding, and signaling apparatus at the central oflice controlled by each said coil, substantially as described.

12. In a telephone system, the combination with a pair of telephone-lines, a pair of repeating-coils to unite said lines for conversation, one winding of each coil connected in the cir- IOO IIO

cuit of each line and in parallel therein, a condenser connected in the middle of one winding in each coil, a source of current connected in the middle o1' the other winding of each coil, a switch at the substation o1' each line controlling the circuit of the said source through the said winding, and signaling apparatus at the central ofiice controlled by each coil, substantially as described.

13. In a telephone system, the combination with a pair of telephone-lines, of a cord-circuit at the central office to unite said lines for conversation, a pair of repeating-coils in said circuit to indu ctively unite the two ends thereof, one Winding of each coil connected in the circuit of each said end, a condenser in the path of current through one winding of each coil, a source of current connected with the other winding of each coil and adapted to be included in the metallic circuit of the telephone-line when a connection is established by the cord-circuit with the lines, a switch at each substation to control the flow of current over the metallic line, and supervisory-signaling apparatus controlled during connection by the said coils, substantially as described.

14. In a telephone system, the combination with telephone-lines, of a cord-circuit at the central oiiice to unite said lines for conversation, a pair of repeating-coils to inductively unite the ends of said cord-circuit, one winding of each coil connected with each end of the cord-circuit and in parallel therein, a condenser connected With one winding of each coil to prevent the passage therethrough o1' continuous currents, a source of continuous current connected in the middle of each of the other windings of said coils and adapted to be included in the metallic talking-circuit when a connection is established and to'furnish current over the connected lines for conversation, and a supervisory signal for each end of the cord-circuit controlled during a connection by the corresponding coil, substantially as described.

15. In a telephone system, the combination with telephone-lines, of a cord-circuit to loop said lines together for conversation, a pair of repeating-coils connected with said cord-circuit to inductively unite but conductively separate the two ends of the same, and a separate source o1' current connected with each end of the cord-circuit and adapted during a connection to furnish current over the corresponding telephone-line for conversation, said repeating-coils being organized to operate as electromagnets, substantially as described.

16. In a telephone system, the combination with telephone-lines, of a cord-circuit to loop said lines together for conversation, a pair o1' repeating-coils connected with said cord-circuit to inductively unite but conductively separate the two ends of the same, a separate source of current connected with each end of the cord-circuit and adapted during a connection to furnish current over the corresponding telephone-line for conversation, said repeating-coils being organized to operate as electromagnets, and a supervisory signal for each end of the cord-circuit controlled by the said coils, substantially as described.

17. In a telephone system, the combination with telephone-lines, of a cord-circuit to loop said lines together for conversation, a pair of repeating-coils connected with said cord-circuit, a winding of each coil connected With each end o1 the cord-circuit, one Winding of each relay being opaque to the passage of continuous current, a separate source of current connected with the other winding of each coil and adapted during a connection to be included in the corresponding telephone-line to furnish current thereover for conversation, said repeating-coils being organized to operate as electromagnets, and a supervisory signal for each end of the cord-circuit controlled during a connection by the corresponding coil, substantially as described.

18. In atelephone system, the combination with telephone-lines, of a cord-circuit to loop said lines together for conversation, a pair of repeating-coils connected with said cord-circuit, a winding in each coil being connected in each end o1' the cord-circuit and in parallel therein, a condenser in series with one winding of each coil, a separate source of current in series'with the other winding of each coil and adapted to be included in the metallic talking-circuit established by the connection of the corresponding end of the cord-circuit with a telephone-line, said repeating-coils being organized to operate as electromagnets, and a supervisory signal for each end of the cord-.circuit controlled by the corresponding repeating-coil, substantially as described.

19. In atelephone system, the combination with telephone-lines, of a cord-circuit to connect said lines together for conversation and having a plug at each end, a signal-controlling electromagnet for each end of the cordcircuit having its actuating-windings connected between the strands thereof, said electromagnets serving also as repeating-coils to inductively unite the two ends of the cord-circuit, a separate charging source of electricity adapted to send current through the actuating-winding of each magnet, a plug-seat switch for each plug, a switch at the substation o1' each line for controlling the circuit of said source through the actuating-winding of the said electromagnet associated therewith, and a supervisory signal for each end of the circuit controlled by the corresponding electromagnet and plug-seat switch, substantially as described.

20. The combination with a cord-circuit having a plug connected at each end, and the strands thereof conductively divided but inductively united, of a signal-controlling electromagnet for each end of the cord-circuit IOO IIO

having its actuating-winding bridged between the strands thereof, said electromagnets serving also as repeating-coils to inductively unite the two ends of the cord-circuit, a separate source of current for each end of the cord-circuit adapted to send current through the actuating-winding of the corresponding electromagnet, a plug-seat switch for each plug, and a signaling device for each end of the cordcircuit controlled by the corresponding electromagnet and the plug-seat switch, substantially as described.

21. In a telephone system, the combination with telephone-lines, of a cord-circuit to loop said lines together for conversation, a pairof repeating-coils connected with said cord-circuit, a winding of each coil connected with each end oi' the cord-circuit, one winding of each coil .being opaque to the passage of continuous current, a separate source of current connected with the other winding of each coil and adapted during a connection to be included in the corresponding telephone-line to furnish current thereover for conversation, said repeatingcoils being organized to operate as electromagnets, a supervisory signal for each end of the cord-circuit, local circuits for said supervisory signals each controlled at one point by said coils and at another point by auxiliary means, substantially as described.

22. In a telephone system, the combination with telephone-lines, of a cord-circuit to loop said lines together for conversation, a pair of repeating-coils connected with said cord-circuit, a windingof each coil connected with each end of the cord-circuit, one winding of each coil being opaque to the passage of continuous current, a separate source or' current connected with the other winding of each coil and adapted during a connection to be included in the corresponding telephone-line to furnish current thereover for conversation, said -repeatingcoils being organized to operate as electromagnets, a supervisory signal for each end of #einer the cord-circuit operated over local circuits,

as to deprive said signals of operating-current during conversation to render them inert at that time, and other means for controlling said circuits to likewise deprive said signals of operating-current when the cord-circuit is not connected with the lines whereby said signals are normally inert, substantially as described.

23. In a telephone system, two line-circuits, means for supplying electric energy thereto` a primary induction-coil in each of said linecircuits, and a secondary coil connected in each line-circuit in shunt around the source of electrical supply therefor', and arranged in inductive relation to the primary coil of the opposite line-circuit.

24. In a telephone system, the combination with two line-circuits, means for supplying electric energy thereto, a pair of repeatingcoils, a primary winding of said coils included in each of said line-circuits, and a secondary winding of said coils connected in each linecircuit in shunt around the source of electrical supply therefor and arranged in inductive relation to the primary coil of the opposite linecircuit, vsubstantially as described.

25. In a telephone system, the combination with two line-circuits, a pair of repeatingcoils at the central ofce having inductivelyassociated windings to unite said circuits for conversation, each said coil having a winding connected in each circuit, said windings in each circuit being connected in parallel with said coils controlling the said local circuits soV each other, and means for supplying current to said line-circuits for conversational purposes, substantially as described.

In witness whereof I have hereunto subscribed my name in the presence of two witnesses. l

JOHN HENRY LENDI. Witnesses:

KEMPSTER B. MILLER, WM. W. DEAN. 

